BoostBuggy

I have an issue here. My 86 951 will not pass Colorado emissions. It's coming in too high (rich) on the HC & NOx. And I can't renew the plates without first passing emissions. (And I already have one $150 expired tabs ticket)

FWIW, I did a dyno pull a couple of months ago and starting at just shy of 3.5k RPM the AFR starting going rich. By 4k RPM the AFR had taken a nose dive off the bottom of the graph. The graph bottomed out at 10 AFR and the line showing my AFR was headed WAAAAY south.

It was suggested I do an oil change and tune up. So I replaced the plugs, coil, distibutor cap and rotor and did the oil change, all within the last couple of days. And basically have not driven the car until this morning on the way to emissions. It still is running wWAAAAY rich and will not pass emissions.

I'm at wit's end and looking for help on this.

Suggestions? Remedies?

Ronin-951

Check your DME Temp Sensor, and your O2 Sensor, per Clarks.

BoostBuggy

Thx. I'll look those up on Clark's and give them a check. Depending on what they cost it might simpy be easier to replace them and be done with it. The car certainly has enough miles on it to warrant such.

odb812

Check for vac leaks.

Rogue_Ant

We need more info... What mods are done to the car? Can you post your test results? They have tightened emissions in the past few years, but we can still get the cars to pass without too much hassle.

BoostBuggy

Sure Rogue_Ant, I can give you specifics.....

I have to find the dyno jpg and re-upload. Gimme a few minutes and I have it up

odb812

A list of modifications would help too.

BoostBuggy

OK, dyno pull here

Mods, not much. Has an Autority #2 chip and a LR Downpipe. That's it.

The emissions run today resulted in HC = 2.9757 (max is 2.5) and NOx = 4.7857 (limit 4.5) CO = 15.2896 (passed) and CO2 = 350.9973

Hope this helps.

BoostBuggy

BTW, dyno pull was 6 Mar 12 and was on the old plugs, coil, dist cap & rotor and OLD oil

BoostBuggy

Which O2 sensor to purchase? The Bosch OE part is $133 @ Pelican and there are Bosch Universals for as little as $15.

It appears the Bosch OE part is a 2 wire. Is this correct? Do I have to have 3 sires or will a 1 wire work? I want the correct part but if I can get something that works for $15 that's much better than spending $133!

Thx for the help guys.....

Rogue_Ant

Ok, you are not that far off, and your limits aren't the tightest around - we can definitely get the car to pass.

When on the emission rollers you want to keep the car out of boost as much as possible. So if you are using an aftermarket boost controller, then lower it all the way.

Next, have you checked to make sure your altitude sensor is plugged-in?

Do you have your stock DME chip? What FQS position were you on?

On the dyno, it looks like the car is correcting to stoich (a good thing), so it appears that your O2 sensor is working.

How long did you drive before testing? It really helps to get the exhaust HOT before testing - if you can touch it, then it isn't hot enough.

For the O2 sensor check here:

http://www.the944.com/oxygen.htm

BoostBuggy

Well first off I'm not driving the car when it's on the rollers. The emissions tech does that and I'm of the understanding ACC will not allow you to drive the car (although a monkey could probably do it) If there's another CO emission vendor that will allow you to drive the car please let me know about it.

I assumme the altitude sensor is plugged in. The car passed emissions without issue in 2010 (last time it was checked - I skipped a year somehow) Where is the altitude sensor?

I have the stock DME chip(s). What is the FQS? I have no idea what you're referring to here.

I'll say I drove it around 5 miles from my house to the emissions place. The water temp guage was showing it was at normal operating temp.

Rogue_Ant

There isn't a place that will let you drive it... I was simply referring to what needs to be done to car regardless of who is driving.

Double-check that your altitude sensor is plugged in - it matters up here. If not, then you are immediately 6% too rich. And judging by your dyno, you are WAY too rich once the car is in boost (hence my point of doing what you can to keep the car out of boost on the rollers).

The FQS is the little rotary switch located on/in the DME:

http://www.motronic.ws/fqs.htm

It is on the DME, opposite side from the wiring plug.

5 miles is no where near enough to warm up the exhaust. The oil probably wasn't even fully warm yet either. Rule of thumb, it takes 2-3 times as long for the oil to heat up compared to coolant.

odb812

FQS:
http://www.lindseyracing.com/LR/Parts/DMEFQSSWITCH.html

Rogue_Ant

Good link - better pictures. But the fuel enrichment settings will not be correct for the Autothority chips...